1. Field of the Invention
The present invention relates to a magnetic head slider for a floating magnetic head. More particularly, it relates to a magnetic head slider for a floating magnetic head which is especially suitable for removing particles, such as dust, adhering to the disk surface of a magnetic disk unit.
2. Description of the Related Art
In general, to achieve high recording density in magnetic head units, the float gap (flying height) between a magnetic head and the recording medium of a magnetic disk unit tends to be narrow. Because of this narrowness, particles on the magnetic disk surface may become caught by tapered portions on inflow ends of magnetic heads, and intrude into the float gap between the magnetic head and the magnetic disk, thereby causing recorded information temporarily not to be read. Particles adhering to the magnetic disk surface may further be buried in a magnetic film of the magnetic disk, thereby leading to the problem of sliding. The possibility of such a problem has been increasing.
There are two methods of removing particles adhering to the magnetic disk surface. One is to clean the single magnetic disk before the disk is incorporated into an HDA (Head Disk Assembly). The other is to remove micro-particles, such as dust, present on the magnetic disk after the disk has been incorporated into the HDA, whereby the magnetic disk is prevented from being damaged.
Japanese Patent Unexamined Publication No. 57-179969 discloses a method of preventing abrasion. In this method, rails, which act as floating faces of a magnetic head slider, have hitherto been substantially parallel to a tangential velocity vector line of the rotatable magnetic disk. Skew angles are formed on the magnetic head slider so that slightly oblique angles are formed with respect to the tangential velocity vector line on the track of the magnetic disk. Because of the above arrangement of the magnetic head slider, micro-particles such as dust strike against the back edge of the magnetic head slider having the magnetic head, thereby preventing the magnetic disk from abrasion.
Furthermore, Japanese Patent Unexamined Publication No. 58-111164 discloses a method of cleaning a magnetic disk surface. In this method, a substantially square magnetic head slider is provided at slightly oblique angles, or skew angles, with respect to a tangential direction on the track of a magnetic disk surface. Because of the skew angles in this arrangement, for a seeking direction in which slider sides are positioned in front of inflow ends, particles adhering to the magnetic disk first come in contact with the slider sides. These particles which are in contact with the slider sides are scraped away by the slider sides, and are then carried along the surfaces of the slider sides, whereby the magnetic disk surface is cleaned.
Moreover, Japanese Patent Unexamined Publication No. 60-47278 discloses a method of preventing the abrasion of a magnetic head element. In this method, a magnetic head slider is constructed in such a manner that the width of the magnetic head slider on its front end is the same as that of the magnetic head slider on its back end with respect to movement directions of a magnetic recording medium. A longitudinal sharp line is so formed as not to be parallel to an outline. Thus, a floating face is formed on which pressure is generated to maintain the small gap between the surface of the magnetic recording medium and the head slider.
In addition, Japanese Patent Unexamined Publication No. 61-230687 discloses a head slider. In a magnetic head for an air floating magnetic disk, this head slider, composed of a single rail, is provided with tapered portions so that the width of the rail becomes wider as it approaches an outflow end of the slider. Thus, the entire head slider is shaped into a trapezoid. Because of this shape, the head slider is insensitive to air flowing at an angle oblique to relative movement directions of the slider and of the disk.
In all of the conventional art disclosed in Japanese Patent Unexamined Publication Nos. 57-179969, 58-111164, and 60-47278, when a magnetic head slider having a plurality of rails which are parallel to each other is positioned over a magnetic recording medium, the rails are arranged at slightly oblique angles so that the rails are not parallel to a tangential vector line on the rotatable magnetic recording medium, or the rails are previously arranged so that they are not parallel to the external sides of the magnetic head slider. Skew angles are thus formed, whereby the slider sides scrape away particles adhering to the magnetic disk surface. For the above reasons, the seeking direction limits the effects of cleaning.
In other words, when seeking is made in one direction in which the slider side is scraping away particles adhering to the magnetic disk surface, the adhering particles are removed from the magnetic disk surface, whereby the magnetic disk surface is cleaned. On the contrary, when seeking is made in the opposite direction, particles adhering to the magnetic disk surface are not scraped away. These adhering particles are caught by the tapered portions on the head inflow ends, and are then buried in a magnetic film of the magnetic disk. The particles thus buried in the magnetic film of the magnetic disk cause damage to the magnetic disk and the head surface, whereby the magnetic disk surface is not cleaned.
However, while the magnetic head unit is in operation, powder and dust caused by abrasion of the unit components are constantly generated. Moreover, the magnetic head performs seeking operations very frequently in both directions. The cleaning methods of the conventional art are not sufficient for cleaning the magnetic disk surface.
Furthermore, in the conventional art disclosed in Japanese Patent Unexamined Publication No. 61-230687, a method of removing particles adhering to the disk surface is not considered. In addition, since the head slider is of single rail type, the floating stability of the head is low while the head is operating, as compared with the floating stability of a head having a plurality of rails such as a two-body type head. Thus, this head slider is not suitable for low floating heads.